English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background    Clostridium thermocellum  utilizes a wide variety of free and cellulosomal cellulases and accessory enzymes to hydrolyze polysaccharides present in complex substrates. To date only a few studies have unveiled the details by which the expression of these cellulases are regulated. Recent studies have described the auto regulation of the  celC  operon and determined that the  celC – glyR3 – licA  gene cluster and nearby  manB – celT  gene cluster are co-transcribed as polycistronic mRNA.    Results  In this paper, we demonstrate that the GlyR3 protein mediates the regulation of  manB.  We first identify putative GlyR3 binding sites within or just upstream of the coding regions of  manB  and  celT . Using an electrophoretic mobility shift assay (EMSA), we determined that a higher concentration of GlyR3 is required to effectively bind to the putative  manB  site in comparison to the  celC  site. Neither the putative  celT  site nor random DNA significantly binds GlyR3. While laminaribiose interfered with GlyR3 binding to the  celC  binding site, binding to the  manB  site was unaffected. In the presence of laminaribiose, in vivo transcription of the  celC – glyR3 – licA  gene cluster increases, while  manB  expression is repressed, compared to in the absence of laminaribiose, consistent with the results from the EMSA. An in vitro transcription assay demonstrated that GlyR3 and laminaribiose interactions were responsible for the observed patters of in vivo transcription.    Conclusions  Together these results reveal a mechanism by which  manB  is expressed at low concentrations of GlyR3 but repressed at high concentrations. In this way,  C. thermocellum  is able to co-regulate both the  celC  and  manB  gene clusters in response to the availability of β-1,3-polysaccharides in its environment.    Electronic supplementary material  The online version of this article (doi:10.1186/s13068-017-0849-2) contains supplementary material, which is available to authorized users.

The LacI family protein GlyR3 co-regulates the celC operon and manB in Clostridium thermocellum